40G ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



its turn to the concrete. This process goes on continually 

 till the lime in the concrete is saturated with silica. In this 

 way, within a week, the strength of the concrete is increased 

 from fifty to one hundred and fifty per cent., and to a still 

 greater degree by a longer immersion. As the alkali acts 

 only as a carrier of the silica, it is used over and over again, 

 and it is in this that the economy of the manufacture consists. 

 The substance thus formed is known as silicated concrete, or 

 the patent Victoria stone, and it has been manufactured on 

 a grand scale in London, and several large edifices have been 

 built entirely from it. The economy of its construction is 

 such that it promises to supersede natural stone, except 

 where the latter is very cheap and abundant. In London it 

 can be put into place in building at a- much less cost than 

 natural stone. 1 A, October 21, 195. 



AP03NITE, A NEW BUILDING MATERIAL. 



A new building material, called apcenite, has lately been 

 brought to notice as manufactured by the Patent Concrete 

 Stone Company at East Greenwich, England. This, an arti- 

 ficial granite or marble, is concreted in a mould by the action 

 of chloride of calcium and water-glass, combined with a body 

 of Derbyshire spar or other material. It hardens quickly, 

 and attains an ultimate crushing strength of three tons per 

 square inch, equaling that of granite. It exhibits perfect 

 sharpness and delicacy of moulding, besides admitting an ex- 

 quisite degree of polish. It is also said to be unaffected by 

 exposure to the weather or by acids, and to be produced at a 

 less cost than scagliola or enameled slate. The same compa- 

 ny manufactures a silicious paint, consisting of water-glass, or 

 silicate of soda, combined with steatite, clay, or other incom- 

 bustible element, and a coloring medium. This dries quickly, 

 with a hard surface, and good, clear body color, and possess- 

 ing extraordinary power of resistance to fire. In one experi- 

 ment, the boarding and roofing of the wooden structures 

 which were set on fire had been covered with the silicious 

 paint, which was exposed to the full force of the flames 

 twenty minutes, and, though the paint blistered and perished, 

 it effectually preserved a large extent of wood-work from in- 

 jury. 3 A 9 July 29, 69. 



